Electric time switch



Sept. 23, 1969 H. ELFERS 3,469,108

ELECTRIC TIME SWITCH Filed July 14, 1966 3 SheetsSheet 1 P 1969 H.ELFERS ELECTRIC TIME SWITCH 3 Sheets-Sheet 2 Filed July 14, 1966 Sept.23, 1969 H. ELFERS 3,469,103

ELECTRIC TIME SWITCH Filed July 14. 1966 3 Sheets-Sheet 5 Fig. 4

Fig. 5

United States Patent 3,469,108 ELECTRIC TIME SWITCH Henry Elfers,Hamburg, Germany, assignor to Lumoprint Zindler KG, Hamburg, Germany, acorporation of Germany Filed July 14, 1966, Ser. No. 565,125 Claimspriority, application Germany, July 21,1965,

Int. (:1. H6111 7/14 US. Cl. 307-141 7 Claims ABSTRACT OF THE DISCLOSUREA timing switch incorporating a spring-biased trigger in slidingengagement with the armature of a relay having a set of load contactsand a set of switching contacts. A momentary depression of the triggerreleases the armature resulting in the closure of the load contacts fora predetermined time interval as determined by the constants of anelectrical timing circuit controlling the energization of the relayoperating coil through the switching contacts. Upon energization of theoperating coil, the trigger automatically returns into blockingengagement with the armature, thereby limiting actuation of the timeswitch to a single operating cycle of controlled time interval. When thetrigger is retained in the depressed position the armature is free tooperate in the normal manner and the timing circuit eifects repetitiveenergization of the relay operating coil, thereby resulting in arepeated series of controlled time intervals.

This invention relates to an electric time switch for controlling anevent which can be initiated by electrical excitation, such time switchcomprising a manual trigger for initiating the operation and a relayconnected in an electrical circuit and operating in mechanicalconjunction with the manual trigger.

It has already been proposed to construct such a time switch so thatswitching oil takes place after the expiration of a time intervalindependent of whether the manual trigger has yet been operated or not.This is particularly important if very short times are to be controlled.

A usual time switch, particularly 'for exposure or illumination deviceson copying machines, in which the abovementioned event is the exposuretime, is adjustable within a fixed interval of some 2. to 6 seconds.Certain qualities of paper, or even colored sheets which need to becopied now and then, frequently require a longer exposure. This ispossible with so-called surface exposure machines in which the sensitivematerial and the pattern can remain for any length of time on theexposure device. The known timers, however, do not permit the processingof such difficult materials which require relatively long exposuretimes, and possibly occasionally even a trans-illumination exposure, andunder such circumstances one has to trigger the time switch severaltimes and let the light penetrate through each time. This process iscomparatively involved and expensive, since not only is additionalmanual operation necessary, but in addition and more particularly themachine is badly utilized in the making of large numbers of copies,since there always remains a certain pause between the individualexposure intervals.

A further consideration arises in respect of those simpler machines inwhich a pressure plate is not pre-tensioned for operation but is presseddown by hand, namely, that the operator having to perform an additionalactuation of the time switch can lead to a displacement of the machineor of the plate which is pressed down manually, with the result that thecopies are rendered useless.

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' ger, but without the need for multiple actuation thereof.

This is achieved in accordance with the present inven tion in that atime control arrangement is provided which, upon release, provides arepeated series of controlled time intervals, and which includes amanual trigger which in its operated position permits a repetition ofthe time intervals by disengagement of a stop and which after itsrelease is movable back at the end of the time interval during which itis released into its initial position in which the stop preventsoperation of the time control arrangement in order to cut-oft anddisconnect the time control device.

In particular, the invention provides that the manual trigger isprovided with said stop which co-operates with a contact-actuating relayarmature and which mechanically holds the relay armature when the manualtrigger is released in a position corresponding to energization of therelay, but which upon actuation of the manual trigger allows the relayarmature to move into a position correspondmg to de-energization of therelay. The invention also provides a time control element which isrendered operative by the operation of the manual trigger, as is also acontrol contact for the event, the time control element being arrangedto open the control contact for a short time upon energization of therelay. The invention also provides that with the manual trigger in itsoperated state and with the stop disengaged a further control process isfree to take place through de-energization of the relay.

Preferably, the invention makes use of a time control arrangement whichincludes a capacitor, the adjustable charge on the capacitor determiningthe time constant and the relay being connected in the capacitordischarge circuit. Thus, a repeated tripping or initiating of the relayinto its operative state is ensured so long as the stop is disengagedfrom its contact with the relay armature as a result of actuation of themanual trigger.

In a preferred embodiment, two relay contact switches are provided whichare engageable through the agency of the manual trigger, one of whichswitches controls the electrical excitation for the event which is beingcontrolled and additionally closes a charging circuit for the capacitor,which the other of said switches is a changeover switch which switches apreionizable circuit element from a by-pass circuit into the dischargecircuit of the capacitor so that constant switching times are achievedfrom the first controlled event onwards.

The change-over switch is preferably a single-pole triggered first opensonly after the other changeover switch contact has closed.

In another preferred embodiment of the invention, the manual trigger isformed as a push-button, and the stop is formed as a stepped, enlargedportion of the stem of the push-button and operates under the action ofa spring which attempts to urge the manual trigger into its said initialposition. This enlarged portion of the push-button stem is associatedwith the relay armature in such manner that it is movable upon releaseof the manual trigger to a position in front of the armature which islocated in the relay-energized 0r attracted position, and is constructedin such manner that it includes a step on which the armature, whenlocated in its de-energized position, supports itself in an easilyslidable manner.

In order that the invention may be fully understood, an embodimentthereof will now be described in detail by way of example and withreference to the accompanying drawings, in which:

FIG. 1 is an electrical circuit diagram of a time switch in accordancewith the present invention;

FIGS. 2 and 3 are schematic side views of the manual trigger whichco-operates with the relay in the circuit as shown in FIG. 1; and

FIGS. 4 and 5 are two different side views of the relay contactsrespectively illustrating the two separate switches which are controlledby the relay armature and which are represented in FIG. 1.

According to FIG. 1, an energy source 1 is provided, for example from asocket switch or a voltage terminal, and in the present case is a sourceof 220 volts A0. A circuit mesh 4 is connected across the voltage sourceby means of two supply leads 2 and 3 and in the present embodiment anexciter lamp 5 is connected in the circuit mesh 4. This exciter lamp 5is the element to be controlled by the time switch. The lamp 5 isswitched into the circuit mesh 4 by means of an onoif /contact switch 6,to be described in more detail later with reference to FIG. 5. For thecontrol of other events or processes, for example for controlling aservo-motor, a suitable control device for the servo-motor may beprovided instead of the lamp 5.

The supply leads 2 and 3 also feed a further circuit mesh 7 which isconnected across the supply leads 2 and 3 and which has a capacitor 8,for example of approximately 250 pf., and also a relay valve 9 connectedtherein. The relay valve 9 may have, for example, a firing voltage ofapproximately 200 volts and a cutoff potential of 50 volts. So long asthis valve has not yet been actuated, it will first give a currentoutput of the desired value when the potential of 200 volts is reached.However, it cuts off again when the voltage falls after firing to lessthan 50 volts.

The capacitor 8 ensures that a pre-ionization of the relay valve 9always takes place. This is important in order that the chosen firingvoltage value and cut-off potential value are always maintained exactlyconstant from the very first time that the arrangement is operatedonwards.

A further circuit mesh 10 extends from a point in circuit mesh 4 betweenthe contact switch 6 and the lamp 5 to a point in circuit mesh 7 betweenthe capacitor 8 and the relay valve 9. In this mesh 10 there isconnected in series a current gating device 11, i.e. particularly arectifier, and thereafter a resistance network of resistances 12 and 13,at least one of said resistances, i.e. resistance 13, being adjustablein order to select a fixed time period. The resistances 12 and 13 arepreferably of the order of 100 to 350 KS2.

From the junction point of the circuit meshes 7 and 10 extends a by-passconductor 14 which includes a changeover switch 15, also described laterwith reference to FIG. 4. This change-over switch 15 is a single-poledouble-throw switch having two switching contacts 16 and 17 and arelatively movable switching arm 18 which co-operates with the switchingcontacts 16 and 17 alternately but with a certain time overlap.Switching contact 16 is connected to conductor 14, and switching contact17 is connected by way of a conductor 19 either to circuit mesh 7 at apoint between the relay valve 9 and supply lead 3 as shown or to supplylead 2. The movable switching arm 18 is connected to a circuit mesh 20which includes a relay 21 as well as a capacitor 22, for example of 4mf., connected between the relay 21 and the switching arm 18. Thecircuit mesh 20 has its other end connected to supply lead 3.

The on/ofi switch 6 and the change-over switch 15 have their contactsmounted on the relay 21 and will be described more fully with referenceto FIGS. 4 and 5, particularly in order to show more clearly how it isthat switching contact 17 first opens only after switching contact 16 isclosed upon a reversal of the change-over switch 15.

These contacts are, with reference to the relay, arranged as normallyclosed contacts, i.e. they are open when the relay 21 is energized orwhen the armature of the relay which operates the contacts is located inthe position corresponding to energization, or else they are positionedas shown i.e. the change-over switch arm 18 engaging switching contact17, when switching contact 16 is open.

It will be realized that in the arrangement as shown in FIG. 1 the lamp5 is without current and a pre-ionization current through the relay tubeonly flows through circuit mesh 7. By means which will now be describedthe illustrated position is maintained when the relay is deenergized sothat the relay armature, even with the not yet energized relay in theinitial position of the arrangement, is secured by mechanical means inthe position which corresponds to the de-energized state of the relay.

Upon actuation of this mechanical means, for example by means of amanual switch, the relay armature can move after its release into aposition which corresponds to the not energized relay, since the relay21 finds itself in the initial position in the not energized state andcapacitor 22 can fully discharge itself via circuit mesh 20, conductor19 and a part of circuit mesh 7. This movement can be assisted byspecial springs, or it may take place only as a result of the inherentspring qualities of the contact elements. In this case, the on/offcontact switch 6 closes, the lamp lights up, and a current flows fromsupply lead 2 through circuit mesh 10 since the impedance betweencapacitor 8 and resistances 12 and 13 is suitably chosen so that thecurrent is conducted through circuit mesh 10.

Simultaneously, the change-over switch 15 reverses so that switchingcontact 16 is engaged by the movable contact arm 18. Thus, circuit mesh20 with its capacitor 22 and relay 21 is connected in parallel with thepre-ionized relay valve 9. The capacitor 22 is thus charged up accordingto the magnitude of the variable resistance 13 until it reaches thefiring potential of the relay valve 9. Then, the capacitor 22 dischargesand the relay 21 is operated promptly. By means of the resultantarmature movement the on/oif contact switch 6 and the change-over switch15 return to the illustrated positions, whereupon the abovementionedtime-wise overlap of the switching between switching contacts 16 and 17again occurs. This overlap avoids in a simple way any contact bounce andensures thereby that the whole discharge of the capacitor contributes tooperating the relay, even when the cut-off potential of the relay valve9 is reached. If in this case the relay armature is freely movable,then, when the current in circuit mesh 20 falls below the cut-out valuefor the relay 21, the relay armature again moves so that the on/ offcontact switch 6 closes and the change-over switch 15 effects movementof its movable arm 18 into contact wiltfh switching contact 16. Theprocess then repeats itse By choice of the switching elements one canensure that the intermediate time between different periods ofenergization of the lamp 5 is extremely short, so that in practice theextinction of the lamp is not in general visible with the human eye.

The mechanical means for effecting the control according to theinvention is shown in FIGS. 2 and 3. In a switch housing, not shown inmore detail elsewhere, and which comprises an upper wall 23 and a baseor lower wall 24, a manual trigger in the form of a push-button ismounted. The button 25 itself is disposed above the upper wall 23, andits stem 26 extends down through apertures 27 and 28 in the respectivewalls 23 and 24 so that the push-button is held perpendicular to thewalls. A cylindrical enlargement 29 is provided on the stem 26 of thepush-button. Between the enlargement 29 and the lower wall 24 isdisposed a pressure spring 30 around the stem of the push-button whichattempts to urge the push-button upwardly, and against its upward forcethe cylindrical enlargement 29 can be moved downwardly by exertingpressure on the button 25.

In the switch housing between the walls 23 and 24 is located the relay21. The relay is constructed in the usual manner. The relay armature 32is pivotably mounted at 31. The relay armature 32 has a first arm 33which is movable in front of the core 34 of the relay 21, and a secondarm 35 which operates the switching contacts of switches 6 and 15 in amanner to 'be described laterwith reference to FIGS. 4 and 5.

The relay armature 32 is movable between the two positions shownrespectively in FIGS. 2 and 3. FIG. 2 shows one position in which thefirst arm 33 contacts the relay core 34 and which corresponds to theenergized state of the relay 21. This position is maintained, by meansof mechanical clamping by the enlargement 29, even in the not energizedstate of the relay when the push-button is displaced upwardly by thespring 30 so that the enlargement 29 can slide in front of said firstarm 33 of the armature.

This position can only be achieved by the enlargement when the relay isenergized at least for a short time so that there is a clear upward pathof movement for the enlargement 29 past first arm 33 of the armature.

When the push-button as shown in FIG. 2 is operated, the enlargement 29is displaced downwardly so far that the relay armature 32, with therelay in the not energized state, pivots or moves in an anti-clockwisedirection. Thus, the lower end of said first arm 33 takes up a positionon a step 36 (FIG. 3) formed by the enlargement 29, so that thepush-button is itself then locked in its lower position even when it isreleased from finger pressure. If the relay is energized in the positionas shown in FIG. 3, then the initial torque on the armature 32 isarranged to be so great that arm 33 can be withdrawn from the step 36,which for example may be bevelled on the left-hand side as viewed inFIG. 3 to facilitate this movement. When arm 3 is withdrawn the spring30 forces the enlargement 29 upwards until a stop 37 at the lower end ofthe stem 26 prevents any further upward movement due to its engagementwith the underside of the lower wall 24. Thus, the position shown inFIG. 2 is again reached.

FIGS. 4 and show respectively different side views of the contact groupsforming the switches 15 and 6 of FIG. 1. These contact groups arearranged side-by-side above said second, actuating arm 35 of the relayarmature 32. The base 38 of the respective switches is, for example,connected to the upper and lower Walls 23 and 24. FIG. 4 shows thechange-over switch 15 mounted above the body of the relay 21 and thearmature 32. Three contact-carrying lamellae 39, 40 and 41 of anelectrically conductive and preferably resilient material project fromthe switch base 38. The uppermost lamella 39 carries two contacts 42 and43 located at different distances from the switch base 38. A contact 44on the central lamella 40' is arranged to co-operate with the contact 42disposed nearer to the switch base 38 on the upper lamella 39, and theother contact 43 on the upper lamella is arranged to co-operate with acontact 45 on the lowest lamella 41. Operation of the switch is effectedby means of a spring clip 46 extending outwardly of the switch base 38.The actuating arm 35 of the relay armature 32 presses against a pressurestud 47 on the underside of the spring clip and a further pressure stud49 depending from the lowest lamella 41 is arranged to contact the upperside of the spring clip. The spring clip 46 is arranged to urge therelay armature 32 into its upwardly or downwardly displaced position. Itwill be realised that, by an energization of the relay, the spring cliprises and the lowest lamella 41 is raised by means of the dependingpressure stud 49' until contacts 43 and 45 close. This corresponds to aclosing of switching contact 17 and the movable arm 18 of the switch 15of FIG. 1. Initially thereafter, with upward movement of the uppermostlamella 39, contact 42 breaks from contact 44, which, with reference toFIG. 1, corresponds to the engagement of switching contact 16 and themovable arm 18. In the reverse process, contacts 42 and 44 close firstbefore contacts 43 and 45 open.

FIG. 5 shows the contact group for the on/otf switch 6 of FIG. 1. Bymeans of the actuating arm 35 of the relay armature 32 a pressure stud47' depending from a spring clip 48 is moved upwards together with thespring clip until the end of the spring clip contacts a stop member 49depending from a lamella 50. This lamella 50 is mounted in the switchbase 38 and carries a contact 51 which is arranged to make with acontact 52 carried by a second lamella 53 disposed between said firstlamella 50 and the spring clip 48. It will be seen that the contacts 51and 52 are urged away from one another when the relay armature 32 comesinto a position corresponding to the energized state of the relay. Thelamellae 50 and 53 and the contacts 51 and 52 form the on/off switch 6of FIG. 1. The breaking of the lamellae corresponds to the positionshown in FIG. 1.

FIGS. 1 and 2 show the initial position. If the pushbutton is then movedinto position shown in FIG. 3, the relay armature 32 moves into itsanti-clockwise pivoted position. The switches 6 and 16 close so that thetime control period begins. If the push-button is released within thistime period, then energization of the relay 21 causes the enlargement 29to return to the position shown in FIG. 2 after the first time periodand the arrangement is again locked in the initial position.

If the push-button is depressed for longer than corresponds to a pre-settime period, then the relay 21 becomes operative and the switches 6 and15 return to their positions as indicated in FIG. 1. Since, however, theenergization of the relay follows as a result of a current pulse fromcapacitor 22, the energized state is very short and the relay armature32 again returns to the position as shown in FIG. 3, Le. it closesitself automatically for a new time control sequence. The exposure timemay be set, for example, for periods of 5 seconds duration. Thus, bydepressing the push-button for only 11 seconds a total time period of 15seconds results.

Since the switching process is audible from the changeover of the relay,or under certain circumstances can be made audible by acoustic means,for example by means of a clapper which co-operates with the armature 32and which strikes against a plate, the operator can easily estimate howlong the push-button must be depressed for a desired period ofillumination. It is essential that only one trigger should have to bemanually operated in order to achieve under any given circumstances anydesired length of controlled illumination, while an immediate release ofthe trigger 25 after individual depressions of the button ensures thatthe device returns to its initial position after the expiration of thepre-set and initiated time period and is then locked in this initialposition. It is surprising that this new principle can be applied toexposure control with such extraordinarily simple means.

The invention has been described with reference to electrical circuitrywhich operates with a chargeable capacitor as the time control element.It will be apparent to one skilled in the art that in order to carry outthis principle of permitting the expiration of a number of time periodsby actuating a manual trigger in proportion to the actuating time,various other means could be used, such as electric motors ormechanically driven elements which co-operate with locking devicesand/or electrical cut-outs, wherein the locking devices and cutouts arecoupled to the manual trigger so that they remain disengaged for longertimes or close by engagement during one time period of the totalcontrolled time with the termination of this time period.

The mechanical arrangement shown in FIGS. 2 and 3 in combination withthe arrangements shown in FIGS. 4 and 5 ilustrate essential features ofthe invention in respect of the mechanical locking of a relay armaturein dependence on pre-set switch positions. The spatial ar- 7 rangementof the parts is also of importance in order to fulfill the lockingfunction satisfactorily.

I claim:

1. A device for controlling an element by electrical means which areconnectable in circuit through a switch, said device comprising,

(a) a relay mounted on a support and having an armature movable betweenfirst and second positions corresponding respectively to thede-energized and energized state of the relay,

(b) switch means cooperating with the armature, which switch meansincludes an on-otf switch which is closed when the armature is in itsfirst position and open when the armature is in its second position,said switch means also including a change-over switch,

(c) a spring-biased, manually-operable trigger carrying a stop andmounted on said support adjacent to said relay, said trigger beingmovable from a normal first position wherein the stop retains thearmature in its second position to a second position wherein the stop ismoved out of the path of travel of the armature,

(d) terminal means for supplying energy for said electrical means andrelay, and

(e) time delay means alternately connected across said terminals andacross said relay by said change-over switch as the armature occupiesits second and first positions respectively, said time delay meansmomentarily energizing the relay a predetermined time interval after thesaid armature moves into its first position; the arrangement being suchthat upon momentary movement of the trigger to its second position thearmature moves to its first position and into the path of travel of saidstop thereby retaining the trigger substantially in its second position,said trigger returning to its first position when the relay isenergized.

2. The invention as recited in claim 1, wherein the said time delaymeans is a capacitor and wherein the said change-over switch comprises apair of switching contacts which are open when the armature is in itssecond position and a pair of shorting contacts which are closed whenthe armature is in its second position; and including a preionizableswitching element connected across the said terminals; circuit elementsconnecting one side of said switching element to said capacitor throughthe said switching contacts; and circuit elements connecting thecapacitor across the relay through the said shorting contacts.

3. A device as claimed in claim 1, in which a capacitor connected inseries with the relay is the time delay means, a first circuit mesh isprovided to connect the electrical means, the relay and said capacitor,said circuit mesh being connectable through sets of switching contactson said change-over switch by means of which said first circuit meshwhich is connected on the one hand to said terminal means can beselectively short-circuited through a first set of contacts of thechange-over switch and can be selectively connected through a second setof contacts of the change-over switch to a second circuit mesh which iscon nected to said terminal means of opposite polarity, and wherein theelement to be controlled is connected between said terminal means inseries connection with said on-off switch.

4. A device as claimed in claim 3, in which a preionizable switchingelement is connected in said second circuit mesh which extends betweensaid terminal means, and wherein the first and second sets of contactsof the changeover switch are connected to the said second circuit meshon opposite sides of the pre-ionizable switching element.

5. A device as claimed in claim 4, in which the preionizable switchingelement is a relay valve which permits current flow therethrough at afixed voltage value, and wherein said second circuit mesh includes asecond capacitor.

6. A device as claimed in claim 4, in which a second capacitor isconnected in said second circuit mesh and a third circuit mesh isprovided which is connected on the one hand between the element to becontrolled and the said on-ofi switch and on the other hand to thesecond circuit mesh at a point between the second capacitor and thepre-ionizable switching element, said third circuit mesh havingconnected therein at least one adjustable resistance in seriesconnection with a rectifier, said resistance being of a value withreference to the said second capacitor that current flows through saidthird circuit mesh which is in parallel with the section of the secondcircuit mesh including the said capacitor upon closure of the on-oifswitch.

7. A device as claimed in claim 4, in which the first and second sets ofcontacts of the change-over switch are so arranged that each set ofcontacts in the closed position is first opened only after the other setof contacts is closed.

References Cited UNITED STATES PATENTS 2,414,081 1/1947 Barclay 317-142X 2,431,195 11/1947 Olving 317-142 X 2,513,396 7/1950 Beck 315-240 X2,949,811 8/1960 Weisglass 317-142 X 3,349,293 10/1967 Peffer 317-142ROBERT K. SCHAEFER, Primary Examiner T. B. JOIKE, Assistant Examiner US.Cl. XJR. 317-142

